The Wheel of Fortune

by Nicholas Mee on November 7, 2017

We never stray far from devices that chop up our days into hours, minutes and seconds. We are now all synchronized and no-one is out of step with the rest of the world. It is difficult to imagine how different life must have been when days came and went and the passage of time was apparent only in the motions of sun, moon and stars.

It seems natural to us that a day is composed of 24 equal hours, but before the invention of the clock the hours of daylight were usually divided into 12 hours, so that hours of summer were longer than hours of winter.

The earliest reasonably accurate timekeepers were clepsydra or water clocks, which were invented at least 2,500 years ago. Clepsydra remained in use in the cathedrals and monasteries of medieval Europe. They were often attached to devices that would strike an alarm bell to call the monks to prayer at appropriate times and this is the origin of the word clock—it derives from the French cloche, meaning bell. Clepsydra were only superseded with the invention of the mechanical clock. Plenty of water is available in England, but it is often not the best place for reading a sundial and this could be one reason why mechanical clocks were first constructed there.

None of the earliest clocks have survived to modern times, but we have a good idea when they were first constructed.

A Holywood Superstar

Diagram showing an eclipse of the moon from De Sphaera Mundi.

John of Holywood was one of the stars of 13th century astronomy. Johannes de Sacrobosco, as he was known to his learned contemporaries, was an Englishman who taught in Paris and wrote the most influential astronomy text of the age De Sphaera Mundi (On the Spherical World).

De Sphaera Mundi is a brief account of the medieval universe summarising all that was known of astronomy. For several centuries it was recommended reading for all university students. Sacrobosco placed the Earth at the centre of the Cosmos and discussed the motion of the sun and planets, the length of the year, the inclination of the Earth’s axis, the size of the Earth and its division into arctic, temperate and tropical zones, even the reasons for eclipses of the sun and moon.

Robert the Englishman taught at the University of Montpellier in France where he wrote a commentary on De Sphaera Mundi that gives us a clue to when the mechanical clock was invented. Writing in 1271 Robert says:

‘Nor is it possible for any clock to follow the judgement of Astronomy with complete accuracy. Yet clock makers are trying to make a wheel that will complete one revolution for every one of the equinoctial circle, but they cannot perfect their work.‘

In other words, clock makers were trying to construct a mechanical device that would rotate in time with the passage of the sun and stars across the sky.

Tick Tock

Robert tells us that in 1271 astronomers were trying (but failing) to construct a mechanical clock. They were missing one crucial component—the escapement. This is a ratchet with interlocking teeth that swings back and forth at a regular pace allowing the gradual release of energy stored in a spring or suspended weight in small uniform steps. It is the escapement that produces the characteristic tick tock of a clock.

Dunstable Priory in the county of Bedfordshire, about 30 miles (50 kilometres) north of London. Credit: Wikimedia – John Armagh.

The problem was soon solved, however, as the earliest reference to the construction of a fully functional mechanical clock is in the Annals of Dunstable Priory for the year 1283. We can, therefore, pin down the invention of the clock almost to within a decade.

The new technology spread rapidly to other important towns and cities in southern England. Within a few years there are reports of clocks in Exeter Cathedral, Old St Paul’s in London, Merton College, Oxford, Norwich Cathedral, Ely Abbey and Canterbury Cathedral, and in subsequent decades they are found in the cathedrals of France and Italy.

Documents from Norwich Cathedral dating to 1322-1325 record the construction of a remarkable astronomical clock by master clockmaker Roger de Stoke. Costing the huge sum of £52 9s 6d, it would have been a mechanical marvel with an elaborate astronomical dial decorated with gilded sun and moon, figures representing the days of the month, and an automaton procession of fifty-nine chorister monks as its crowning glory. Unfortunately, it was destroyed by fire in the 17th century.

The Divine Comedy

The Divine Comedy of Dante Alighieri was written between 1308 and 1320. Dante is shown here with a copy of his epic poem in a fresco by Michelino. Dante’s city Florence appears on the right, while to the left sinners pass downwards to Hell; the seven-terraced Mount Purgatory rises in the background and the spheres of Heaven revolve overhead.

Cantos X and XXIV of Paradise, the third part of the Divine Comedy, contain what may be the earliest literary references to mechanical clocks. In Canto XXIV Dante writes:

So Beatrice; and those elated spirits Formed themselves in spheres around fixed poles, Flashing out like comets while they whirled.

And as wheels turn within the works of clocks, So that the largest seems, to the observer, To stand still while the smallest seems to fly,

Just so those singing rings, to different measures Dancing in swift circles and in slow, Enabled me to judge their wealth of joy.

(trans. James Finn Cotter)

Richard of Wallingford

The astronomer John North made a remarkable discovery in 1965 in the Bodleian Library in Oxford. He found a book written in 1327 describing the design of a mechanical clock—Richard of Wallingford’s Tractatus Horologii Astronomici.

Richard of Wallingford was a blacksmith’s son, born in the year 1292 in the small, but prosperous town of Wallingford. Richard would study at nearby Oxford where he may have been a fellow of Merton College, famous during this period for the Merton School of mathematicians, known also as the Oxford Calculators. Richard constructed various devices for taking astronomical measurements and performing calculations and wrote about astronomy, astrology, trigonometry and his design for a mechanical clock.

In 1327, Richard was elected Abbot of St Albans. He is depicted as a holy geometer with set square and compasses in the 14th century History of the Abbots of St Albans. A close look at Richard’s face shows that it is covered in blemishes. He was described rather uncharitably by his contemporaries as ‘so sorely afflicted with leprosy that he was unable to live the monastic life with others without causing offence’, although he probably suffered from scrofula or king’s evil rather than leprosy.

Richard was a divisive leader who struggled to contain rebellions by disgruntled monks and revolts from local peasants. He believed the abbey needed a sophisticated mechanical clock based on his design, but constructing the clock was very expensive. Even King Edward III was critical when visiting the abbey. Richard told the king there would be monks aplenty to repair the buildings when he was gone, but none could complete his clock.

Not long afterwards, in 1334, the abbot’s bedchamber was struck by lightning and the building burst into flames. This was rather an ominous portent in a superstitious age. Richard’s health declined rapidly following the lightning strike and he was never free from pain again. Having already lost the sight in one eye, as the disease progressed he lost the ability to speak. Two years later, aged 44, he died.

The clock remained incomplete, but Richard’s belief that no-one else could finish his work proved unfounded. Although the next abbot did no further work on the clock, it was completed during the abbacy of Thomas de la Mare who hired the clockmaker Laurence de Stoke to finish the task with the assistance of the monk William Walsham.

The ironwork clock was a mechanical model of the heavens with a face showing the stars of the night sky. The orb of the sun completed one circuit of the face each day, ringing a bell on the hour, and indicating the time on a numbered dial. The moon’s orb was painted half black half white and rotated gradually to model the phases of the moon. The clock also showed the tides at London Bridge, the closest port to St Albans, and may even have predicted eclipses. A revolving wheel of fortune completed the mechanism, which is perhaps appropriate considering the mixed fortunes of Richard’s life.

Unfortunately, the clock no longer exists. It was probably destroyed in the 16th century during Henry VIII’s dissolution of the monasteries.

Rediscovery and Reconstruction

Following his discovery of Richard of Wallingford’s Tractatus Horologii Astronomici in the Bodleian Library, John North translated the manuscript and his interpretation of Richard’s design is the basis for replica clocks including one built in 1988 that is on view today in St Alban’s Cathedral.

Reconstruction of Richard of Wallingford’s clock in St Albans Cathedral.

Hi, The evolution of ‘The wheel of Fortune’ article seems to have been limited to a close area between England and France. History of time measurement, evolution of astronomy/astrologyin other parts of Europe, Egypt, Asian countries did existed contemporarily. Let us acknowledge the pioneering, untired developments brought forward to the mankind.

Dear Lakshmanan
You are absolutely right. The clepsydra seems to have been invented in Babylonia, which would be modern day Iraq. One of the most remarkable such devices was Su Song’s clock constructed in China in the 11th century: Su Song. There is also nothing in the article about sundials. Unfortunately, there isn’t enough room in a single article to cover the development of clocks all around the world.
England in the 13th and 14th century was a bit of a cultural backwater compared to many parts of Europe and Asia, so I was quite surprised when I learnt that the first fully mechanical clocks were probably built there.